1. Field of the Invention
The field of the present invention relates to body support systems that include elements for pressure redistribution and which include one or more internal air flow guides. The system also establishes pathways for drawing heat and moisture away from surface(s) contacting and supporting a reclining body on the body support system.
2. Background
Those that care for persons confined to beds and wheelchairs understand the role body support systems play with respect to the prevention and treatment of pressure ulcers. Pressure ulcers, which are also known as bedsores, pressure sores, and decubitus ulcers, rapidly develop when prolonged pressure, heat, and moisture are applied to the skin. Persons at risk of developing pressure ulcers commonly are those who have one or more medical conditions that render them fully or partially immobile. Their inability to move, or to change positions more frequently when reclining or seated, causes an uncomfortable distribution of pressure applied against the skin that can directly lead to the development of pressure ulcers.
As uncomfortable distribution of pressure is applied against the skin, blood vessels become pinched, which in turn decreases blood supply at sites where pressure is applied. Heat, resulting from friction, rising body temperature, etc., also decreases blood supply at sites where the pressure is applied. And moisture from incontinence, perspiration, and exudate at these sites further exacerbates the skin, first causing bonds between epithelial layers to weaken, and thereafter causing skin maceration. Failure to address prolonged instances of pressure, heat, and moisture also can cause pressure ulcers to become sites that breed infection. These infection sites often lead to illness, and in severe cases—death.
Considering the severe consequences if pressure ulcers are not effectively treated, the ability of body support systems to relieve pressure from building up against the body and to affect heat and moisture levels at support surfaces is critical. Sufficient measures to prevent and treat pressure ulcers should, therefore, include the selection of body support systems that can redistribute pressure, withdraw heat, and draw away or evaporate moisture from support surfaces. Systems that redistribute pressure frequently are classified as either dynamic or static. Dynamic systems are driven, using an external source of energy (typically direct or alternating electrical current) to alter the level of pressure by controlling inflation and deflation of air cells within the system or the movement of air throughout the system. In contrast, static systems maintain a constant level of air pressure and redistribute pressure through use of materials that conform to body contours of the individual sitting or reclining thereon. Quantitative measurement of two parameters—Heat Withdrawal Capacity and Evaporative Capacity—also may be used to indicate a support surface's ability to withdraw heat and evaporate moisture.
Although foam is frequently used in both static and dynamic body support systems, few, if any, systems incorporate foam to redistribute pressure, withdraw heat, and draw away or evaporate moisture buildup at foam support surfaces. While foam has been incorporated into some body support systems to affect moisture and heat, most of these systems merely incorporate openings or profiles in foam support layers to provide air flow paths. In addition, few, if any, systems specify use of internal air flow guides with specific parameters related to heat withdrawal and moisture evaporation (i.e. Heat Withdrawal Capacity and Evaporative Capacity) at foam support surfaces. Hence, improvements continue to be sought.